Many current wireless communication devices incorporate means for receiving a stream of audio and/or video input according to one or more well known protocols and systems such as TCP/IP, IP Multimedia Subsystem, General Access Network, softswitches, and SIP, which may overlap or complement each other. The goal of these protocols are a combination of reliability, economy and rapid response critical to real time delivery of a data stream. Real time, continuous data delivery is critical for comprehension, appreciation and aesthetic effect of multimedia streams. As these features are incorporated onto mobile devices, like cell phones, size and power consumption also becomes a critical design criteria.
Current mobile devices for wireless communications have become quite complex. However, microprocessor means are provided for these mobile devices, where memory and a real time clock are effectively connected to a processor or processors and a control program directs operations of the mobile device. Current mobile devices often have multiple processors. In a well known structure, a host processor and a communications processor provide a mobile device processing. The purpose of the host processor is to off-load the work of processing the local applications and functions of the mobile device from the processing and management of signal traffic for wireless transmissions and receptions for the mobile device. The communications processor provides the processing interface between wireless communications networks, such as cellular or 802.xx wireless LAN's, and the mobile device.
In applying this dual or multiple processing structure to wireless data transmission and reception for the mobile device, the communications processor can be dedicated solely, for the data communication function, operate data link layer processing. The well known five layer model of data packet transmission includes Application, Transport, Network, Data Link and Physical Layers, each operating under well known protocols by way of standards organizations. A communication processor dedicated to data link layer processing leaves the host processor free to operate to provide processing for higher layer protocols. This data link layer processing at the communications processor, in the prior art, is provided either continuously or only upon demand while the host processor is operational. Dedicating the communications processor to data link layer processing is a substantial benefit for maximizing the bandwidth or transmission and reception capacity of the wireless communication link between the mobile device and the wireless network. Such a dedicated communications processor makes it, in effect, always available for the communication of data at the full data capacity of the wireless communication link.
The benefit of maximizing communication capacity of a wireless communication link or connection is at the cost of operating multiple processors in a battery operated mobile device. Operating several processors, while efficient for distribution of processing, consumes substantially more power than equivalent processing taking place on a single processor. Providing a host processor engaging in processing communications protocols above the data link layer and a separate communications processor engaging in processing for the data link layer results in both processors necessarily operating and being active during any wireless communications sessions. It then follows that providing a host processor and communications processor instead of a single processor for the mobile device increases power consumption that reduces talk time and stand-by time of the mobile device.
Current wireless communication devices include cellular phones, wi-fi enabled devices, and other such devices capable of transmitting and receiving packetized data streams. Multimedia communications with mobile devices have increased and will become more important as data communications capacities for wireless communications increases. As the prior art division of data link layer processing into a communications processor will likely continue to preserve the full use of data communication capacity of the wireless link, the problem of increased power consumption by multiple processors in mobile devices will increase as increased data rates encourage greater use of the mobile devices for multimedia transmission and playout. Where a single processor is used for processing all protocol layers, some modes will mitigate power usage (like IEEE 802.11 UAPSD), but if RTP processing is contained on a different processor from the data link layer processing, both processors will need to be active. Power management by simple coordination of processing functions among the processors is not practical in the prior art. As packets flow from processor to processor, each processor may not be able determine if it would be able to enter a low-power inactive mode.
The implementation low power integrated multimedia systems would clearly benefit from improved real-time performance and power saving capabilities. There is a need for a system which similarly provides for processor partitioning of protocols that support adaptive usage of presently devoted processors in wireless communication devices to minimize power usage and to improve real time performance and power management of multimedia streams.